From: Lukasz Majewski <l.majewski@samsung.com>
To: Viresh Kumar <viresh.kumar@linaro.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Eduardo Valentin <eduardo.valentin@ti.com>
Cc: "cpufreq@vger.kernel.org" <cpufreq@vger.kernel.org>,
Linux PM list <linux-pm@vger.kernel.org>,
Jonghwa Lee <jonghwa3.lee@samsung.com>,
Lukasz Majewski <l.majewski@samsung.com>,
Lukasz Majewski <l.majewski@majess.pl>,
linux-kernel <linux-kernel@vger.kernel.org>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
Myungjoo Ham <myungjoo.ham@samsung.com>,
durgadoss.r@intel.com, Zhang Rui <rui.zhang@intel.com>,
linux-samsung-soc@vger.kernel.org
Subject: [PATCH v12 5/7] Documentation:cpufreq:boost: Update BOOST documentation
Date: Fri, 20 Dec 2013 15:24:53 +0100 [thread overview]
Message-ID: <1387549495-809-6-git-send-email-l.majewski@samsung.com> (raw)
In-Reply-To: <1387549495-809-1-git-send-email-l.majewski@samsung.com>
Since the support for software and hardware controlled boosting has been
added, the corresponding Documentation entry had been updated.
Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Myungjoo Ham <myungjoo.ham@samsung.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
---
Changes for v12:
- None
Changes for v11:
- None
Changes for v10:
- None
Changes for v9:
- None
Changes for v8:
- None
Changes for v7:
- None
Changes for v6:
- None
Changes for v5:
- New patch
Documentation/cpu-freq/boost.txt | 26 +++++++++++++-------------
1 file changed, 13 insertions(+), 13 deletions(-)
diff --git a/Documentation/cpu-freq/boost.txt b/Documentation/cpu-freq/boost.txt
index 9b4edfc..dd62e13 100644
--- a/Documentation/cpu-freq/boost.txt
+++ b/Documentation/cpu-freq/boost.txt
@@ -17,8 +17,8 @@ Introduction
Some CPUs support a functionality to raise the operating frequency of
some cores in a multi-core package if certain conditions apply, mostly
if the whole chip is not fully utilized and below it's intended thermal
-budget. This is done without operating system control by a combination
-of hardware and firmware.
+budget. The decision about boost disable/enable is made either at hardware
+(e.g. x86) or software (e.g ARM).
On Intel CPUs this is called "Turbo Boost", AMD calls it "Turbo-Core",
in technical documentation "Core performance boost". In Linux we use
the term "boost" for convenience.
@@ -48,24 +48,24 @@ be desirable:
User controlled switch
----------------------
-To allow the user to toggle the boosting functionality, the acpi-cpufreq
-driver exports a sysfs knob to disable it. There is a file:
+To allow the user to toggle the boosting functionality, the cpufreq core
+driver exports a sysfs knob to enable or disable it. There is a file:
/sys/devices/system/cpu/cpufreq/boost
which can either read "0" (boosting disabled) or "1" (boosting enabled).
-Reading the file is always supported, even if the processor does not
-support boosting. In this case the file will be read-only and always
-reads as "0". Explicitly changing the permissions and writing to that
-file anyway will return EINVAL.
+The file is exported only when cpufreq driver supports boosting.
+Explicitly changing the permissions and writing to that file anyway will
+return EINVAL.
On supported CPUs one can write either a "0" or a "1" into this file.
This will either disable the boost functionality on all cores in the
-whole system (0) or will allow the hardware to boost at will (1).
+whole system (0) or will allow the software or hardware to boost at will
+(1).
Writing a "1" does not explicitly boost the system, but just allows the
-CPU (and the firmware) to boost at their discretion. Some implementations
-take external factors like the chip's temperature into account, so
-boosting once does not necessarily mean that it will occur every time
-even using the exact same software setup.
+CPU to boost at their discretion. Some implementations take external
+factors like the chip's temperature into account, so boosting once does
+not necessarily mean that it will occur every time even using the exact
+same software setup.
AMD legacy cpb switch
--
1.7.10.4
next prev parent reply other threads:[~2013-12-20 14:24 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1370502472-7249-1-git-send-email-l.majewski@samsung.com>
2013-12-02 12:19 ` [PATCH RESEND v10 0/7] cpufreq:boost: CPU Boost mode support Lukasz Majewski
2013-12-02 12:19 ` [PATCH RESEND v10 1/7] cpufreq: Add boost frequency support in core Lukasz Majewski
2013-12-02 12:19 ` [PATCH RESEND v10 2/7] cpufreq:acpi:x86: Adjust the acpi-cpufreq.c code to work with common boost solution Lukasz Majewski
2013-12-02 12:19 ` [PATCH RESEND v10 3/7] cpufreq:boost:Kconfig: Provide support for software managed BOOST Lukasz Majewski
2013-12-02 12:19 ` [PATCH RESEND v10 4/7] cpufreq:exynos:Extend Exynos cpufreq driver to support boost framework Lukasz Majewski
2013-12-02 12:19 ` [PATCH RESEND v10 5/7] Documentation:cpufreq:boost: Update BOOST documentation Lukasz Majewski
2013-12-02 12:19 ` [PATCH RESEND v10 6/7] cpufreq:exynos4x12: Change L0 driver data to CPUFREQ_BOOST_FREQ Lukasz Majewski
2013-12-02 12:19 ` [PATCH RESEND v10 7/7] thermal:exynos:boost: Automatic enable/disable of BOOST feature (at Exynos4412) Lukasz Majewski
2013-12-04 6:59 ` [PATCH RESEND v10 0/7] cpufreq:boost: CPU Boost mode support Lukasz Majewski
2013-12-04 14:12 ` Eduardo Valentin
2013-12-09 10:04 ` Lukasz Majewski
2013-12-13 16:38 ` [PATCH v11 " Lukasz Majewski
2013-12-13 16:38 ` [PATCH v11 1/7] cpufreq: Add boost frequency support in core Lukasz Majewski
2013-12-13 16:38 ` [PATCH v11 2/7] cpufreq:acpi:x86: Adjust the acpi-cpufreq.c code to work with common boost solution Lukasz Majewski
2013-12-13 16:38 ` [PATCH v11 3/7] cpufreq:boost:Kconfig: Provide support for software managed BOOST Lukasz Majewski
2013-12-13 16:38 ` [PATCH v11 4/7] cpufreq:exynos:Extend Exynos cpufreq driver to support boost framework Lukasz Majewski
2013-12-13 16:38 ` [PATCH v11 5/7] Documentation:cpufreq:boost: Update BOOST documentation Lukasz Majewski
2013-12-13 16:38 ` [PATCH v11 6/7] cpufreq:exynos4x12: Change L0 driver data to CPUFREQ_BOOST_FREQ Lukasz Majewski
2013-12-13 16:38 ` [PATCH v11 7/7] thermal:exynos:boost: Automatic enable/disable of BOOST feature (at Exynos4412) Lukasz Majewski
2013-12-19 14:50 ` Eduardo Valentin
2013-12-20 14:24 ` [PATCH v12 0/7] cpufreq:boost: CPU Boost mode support Lukasz Majewski
2013-12-20 14:24 ` [PATCH v12 1/7] cpufreq: Add boost frequency support in core Lukasz Majewski
2013-12-20 14:24 ` [PATCH v12 2/7] cpufreq:acpi:x86: Adjust the acpi-cpufreq.c code to work with common boost solution Lukasz Majewski
2013-12-20 14:24 ` [PATCH v12 3/7] cpufreq:boost:Kconfig: Provide support for software managed BOOST Lukasz Majewski
2013-12-20 14:24 ` [PATCH v12 4/7] cpufreq:exynos:Extend Exynos cpufreq driver to support boost framework Lukasz Majewski
2013-12-20 14:24 ` Lukasz Majewski [this message]
2013-12-20 14:24 ` [PATCH v12 6/7] cpufreq:exynos4x12: Change L0 driver data to CPUFREQ_BOOST_FREQ Lukasz Majewski
2013-12-20 14:24 ` [PATCH v12 7/7] thermal:exynos:boost: Automatic enable/disable of BOOST feature (at Exynos4412) Lukasz Majewski
2014-01-10 6:35 ` Zhang Rui
2014-01-07 6:58 ` [PATCH v12 0/7] cpufreq:boost: CPU Boost mode support Lukasz Majewski
2014-01-08 0:35 ` Rafael J. Wysocki
2014-01-09 7:19 ` Lukasz Majewski
2014-01-10 6:33 ` Zhang Rui
2014-01-16 9:40 ` Lukasz Majewski
2014-01-16 15:51 ` Rafael J. Wysocki
2014-01-16 15:56 ` Lukasz Majewski
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